The grasping hands in conventional industrial robots have hitherto been proposed in many cases as those for use in in-plant production of products and for precision handling of particular components. On the other hand, the grasping hands for robots that are expected to play active part in household chore support or work support in home, office, hospitals, or the like, as well as in care aid for the aged or the physically impaired and the like are required that the grasping hands themselves be small-sized, lightweight, soft and safe, and moreover capable of dexterously grasping various objects.
With a view to dexterously grasping various objects, a man-type robot hand for research use is disclosed in the Papers of Society of Mechanical Engineers, 66, 651C, 3672/3678 (2000). This robot hand has one 4-joint and 4-degree-of-freedom thumb and four 4-joint and 3-degree-of-freedom fingers, where joints at front ends of the four fingers are provided by link mechanisms and the other joints, in each of which a small-size servomotor is incorporated, is equipped with distribution-type pressure sensors. The robot hand, which has been commercially available for research use, is expensive and restrictive of its use because of its being an assembly of many components.
Also, as a grasping hand in which the grasping hand itself has a soft structure, there has been disclosed in Japanese Examined Patent No. 3226219 a grasping actuator formed of a cylindrical elastic body in which its interior is isolated in three chambers by partition walls. This actuator, while movably operable softly in every direction, yet has difficulties in securely grasping relatively heavyweight articles and in control of its grasping operations because of its having no skeletal structure.
In these prior art examples of grasping hands that have already been reported, there has been disclosed neither a grasping hand nor a robot using the grasping hand, related to the present application, which is driven by a planar-type multi-joint drive mechanism made of a plurality of bone members disposed in array and which is capable of grasping various objects and moreover sample in structure and manufacturable with low cost.
In order to realize and popularize personal robots for household chore support in home or the like, it is an important issue to realize, as a grasping hand to be used in those robots, a grasping hand in which the grasping hand itself is small-sized and lightweight, soft and safe and which has a performance of dexterously grasping various objects and further which is simple in construction and low in manufacturing cost.
An object of the present invention is to provide a multi-joint drive mechanism which can solve the above issues and which has a concrete structure of practicable level including a simplicity of its manufacture as a drive mechanism, and also to provide a manufacturing method for the drive mechanism as well as a grasping hand and a robot using the mechanism.